JP2006297992A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire which is good in driving and braking performances on both of a wet road surface and an iced/snow-covered road surface in such a manner that the extending directions especially of a side cross groove located on both side block trains and a side sipe are rationalized. <P>SOLUTION: On a tread section 1, a pair of circumferential direction main grooves 2 and 3, and a large number of the side cross grooves 6 and 7 are arranged. In this case, the side cross grooves 6 and 7 are tilted to the tire width direction W, and at least extend from the tread ends 4 and 5 until being opened to a closer one of the circumferential direction main grooves 2 and 3. Then, the side block trains 10 and 11 comprising a large number of side blocks 8 and 9 which are divided by the circumferential direction main grooves 2 and 3, the side cross grooves 6 and 7, and the tread ends 4 and 5 are formed. Side sipes 12 and 13 are arranged on respective side blocks 8 and 9, and both of the side cross grooves 6 and 7 which are located on both side block trains 10 and 11 have a tilt in the same direction, and also, the side sipes 12 and 13 located on both side block trains 10 and 11 have a tilt in the opposite direction from the tilt of the side cross grooves 6 and 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic tire having a tread pattern that is located in both side block rows and is arranged so that both side transverse grooves that define and form side blocks are inclined in the same direction. The present invention relates to a pneumatic tire excellent in driving and braking performance on both wet road surfaces and icy and snow road surfaces.

In the conventional tire having such a tread pattern, both side transverse grooves located in the both-side block row are arranged in the same direction, and the side sipes arranged in each side block are also arranged on the side. Generally, it is disposed with an inclination in the same direction as the transverse groove (for example, Patent Document 1).
JP-A-7-132711

  However, as shown in FIG. 4, such a conventional tire defines a block 103 in which the shape of the preceding grounding contour line F is located in one side block row 101 when viewed on the block in the tire contact area S. The transverse groove 104 and the sipe 105 are inclined in the same direction as the extending direction, but are opposite to the extending direction of the transverse groove 107 and the sipe 108 that define the block 106 located in the other side block row 102. On the other hand, the shape of the subsequent grounding contour line B is inclined in the same direction as the extending direction of the transverse grooves 107 and sipes 108 that define the blocks 106 located in the other side block row 102, As a result of the inclination in the direction opposite to the extending direction of the transverse groove 104 and the sipe 105 that define the block 103 located in one side block row 101, Edge effect when heading and kicking, not sufficiently obtained only in one of the side block row, as a whole tire, there is a tendency to lack the drive and braking performance on a wet road, snow, or ice road surface.

  The object of the present invention is to optimize the lateral transverse grooves and side sipes extending particularly in the side block rows, and to effectively obtain the edge effect during stepping and kicking out in the side block rows. Accordingly, it is an object of the present invention to provide a pneumatic tire excellent in driving and braking performance on both a wet road surface and an icy / snow road surface.

  In order to achieve the above object, the present invention provides a tread portion, a pair of circumferential main grooves that are located across the tire equator and extend along the tire circumferential direction, and are inclined with respect to the tire width direction, from the tread end, A large number of lateral transverse grooves extending at least until the circumferential circumferential main groove opens, and a large number of lateral sides defined by the circumferential main groove, the lateral transverse groove and the tread end. In a pneumatic tire in which side block rows made of blocks are formed, and side sipes are arranged on each side block, the side transverse grooves located in the both side block rows have the same direction of inclination. And the side sipe located in a both-sides block row | line has both the inclination of the opposite direction to the inclination of the said side crossing groove | channel, It is a pneumatic tire characterized by the above-mentioned.

  In the present invention, (1) the lateral transverse groove has a continuous curved shape, and (2) the lateral transverse groove has a large extension angle with respect to the tire width direction at the tread end position. (3) The lateral sipe has a large extension angle with respect to the tire width direction at the tread end position and is small at the circumferential main groove position, and (4) the circumferential direction. Two circumferential sub-grooves extending along the tire circumferential direction and a central transverse groove communicating with both circumferential sub-grooves are arranged between the main grooves, and are divided by the both circumferential sub-grooves and the central transverse groove. A central block row of a plurality of central blocks is formed, a central sipe is disposed in each central block, and the central transverse groove and the central sipe are both substantially parallel to the tire width direction; (5) One side transverse groove communicates with the central transverse groove Forming a groove, (6) the lateral transverse groove and the side sipe both have an extension angle of 50 ° or less with respect to the tire width direction, and / or (7) in the vehicle mounting posture of the tire, More preferably, the composite transverse groove located inside the vehicle is longer than the other lateral transverse groove located outside the vehicle.

  According to the present invention, in particular, the lateral transverse grooves and side sipes extending in the side block rows are optimized in the extending direction, and the edge effect when stepping on and kicking out is effectively obtained in the side block rows. As a result, it has become possible to provide a pneumatic tire excellent in driving and braking performance on both wet and icy and snowy road surfaces.

  FIG. 1 shows a part of a tread pattern of a pneumatic tire according to the present invention.

  The pneumatic tire having the tread portion 1 shown in FIG. 1 includes a pair of circumferential main grooves 2 and 3 that extend along the tire circumferential direction C and are located on the tread portion 1 with the tire equator EL interposed therebetween. A plurality of lateral transverse grooves 6 and 7 extending at least from the tread ends 4 and 5 to the openings in the circumferential main grooves 2 and 3 closer to the tread ends 4 and 5, respectively, The side blocks 10 and 11 are formed of a plurality of side blocks 8 and 9 defined by the directional main grooves 2 and 3, the lateral transverse grooves 6 and 7 and the tread ends 4 and 5, and each side block is formed. Side sipes 12 and 13 are arranged at 8 and 9, respectively. As described above, by disposing the side transverse grooves 6 and 7 and the side sipes 12 and 13 in the tread portion 1, it is possible to ensure basic performance for traveling on a wet road surface or an icy and snowy road surface.

  And, the main feature of the configuration of the present invention is to optimize the extending direction of the lateral transverse grooves 6 and 7 and the side sipes 12 and 13 located in the both-side block rows 10 and 11, Specifically, the lateral transverse grooves 6 and 7 located in the both-side block rows 10 and 11 both have the same direction of inclination, and the side sipes 12 located in the both-side block rows 10 and 11, 13 has an inclination in a direction opposite to the inclination of the lateral transverse grooves 6 and 7.

  The “slope in the same direction” as used herein specifically refers to the center of the lateral transverse groove and the side sipe in the XY coordinates with the tire width direction as the X axis and the tire circumferential direction as the Y axis. When a straight line passing through (zero) is assumed, it means that the extending directions are both in the first quadrant and the third quadrant, or in the second quadrant and the fourth quadrant.

  Then, by adopting this configuration, as shown conceptually in FIG. 2, the shape of the preceding grounding contour line F is one side block row 10 when viewed on the block in the tire contact area S. The side block 8 is inclined in the same direction as the extending direction of the lateral transverse groove 6 that defines the side block 8 and the other side block row 11 is also arranged in the side block 9 positioned there. The side transverse sipe 13 is inclined in the same direction as the extending direction. On the other hand, in the other side block row 11, the shape of the subsequent grounding contour line B is a side transverse groove that defines the side block 9 located in the side sipe 13. As a result, the one side block row 10 is inclined in the same direction as the extending direction of the side sipe 12 disposed in the side block 8 located in the side block row 10. Both when stepping on and kicking out The edge effect can be obtained stably in either of the lateral transverse grooves 6, 7 or the side sipes 12, 13, and sufficient driving and braking performance can be obtained on the wet road surface and the ice / snow road surface as a whole tire. In addition, a stable and well-balanced driving / braking performance can be obtained regardless of the direction of the tire mounted on the vehicle.

  Further, it is preferable that the lateral transverse grooves 6 and 7 are basically curved in a continuous point shape in a point-symmetric manner from the viewpoint of eliminating the pattern directionality and improving drainage and snow drainage. .

  Further, the lateral transverse grooves 6 and 7 have an extension angle with respect to the tire width direction W of 50 ° or less, particularly large at the tread end positions 4 and 5 and small at the circumferential main groove positions 2 and 3. This is preferable in that it can be brought close to the shapes of the preceding ground contact contour F and the subsequent ground contact contour B in the tire contact area S, and the driving / braking performance can be further improved. This is because if the extension angle exceeds 50 °, there is a concern about deterioration of uneven wear resistance and ice / snow performance (particularly driving / braking performance).

  In addition, the side sipes 12 and 13 also have a large extension angle with respect to the tire width direction W in the range of 50 ° or less, particularly at the tread end position, as in the case of the side transverse grooves 6 and 7. It is preferable to make it smaller at the circumferential main groove position because it can be brought closer to the shapes of the preceding grounding contour line F and the subsequent grounding contour line B in the tire contact area S, and the driving / braking performance can be further improved. . This is because, if the extension angle exceeds 50 °, as in the case of the lateral transverse grooves 6 and 7, there is a concern about deterioration of uneven wear resistance and ice / snow performance (especially driving / braking performance).

  In particular, if the extending direction of the lateral transverse grooves 6 and 7 and the side sipes 12 and 13 is set so that the angle with respect to the tire width direction is the opposite direction and substantially the same angle, the direction of the tire mounted on the vehicle Regardless, the extending direction of any one of the lateral transverse grooves 6 and 7 and the side sipes 12 and 13 is substantially parallel to either one of the preceding grounding contour line F and the subsequent grounding contour line B. Edge effect.

  Further, as shown in FIG. 1, between the circumferential main grooves 2 and 3, two circumferential sub-grooves 14 and 15 extending along the tire circumferential direction, and a center communicating with both circumferential sub-grooves 14 and 15. A transverse groove 16 is provided to form a central block row 18 composed of a plurality of central blocks 17 defined by the circumferential sub-grooves 14 and 15 and the central transverse groove 16, and each central block 17 has a central sipe 19. Is preferably disposed such that the extending directions of the central transverse groove 16 and the central sipe 19 are substantially parallel to the tire width direction W. Since both the preceding grounding contour line F and the subsequent grounding contour line B are substantially parallel to the tire width direction at the central block position, the contour lines F, B, the central transverse groove 16 and the extending direction of the central sipes 19 This is because the edge effect can be enhanced if they are set so as to match (become parallel).

  Here, “substantially parallel to the tire width direction W” specifically means that the angle with respect to the tire width direction W is within a range of ± 10 °.

  Further, in FIG. 1, it is preferable that one lateral transverse groove 6 communicates with the central transverse groove 16 to form a composite transverse groove, and more preferably, it is located on the inner side of the vehicle in the vehicle mounting posture of the tire. The length L1 of the composite transverse groove is made longer than the length L2 of the other side transverse groove located outside the vehicle. With this configuration, it is possible to effectively use the block edge effect on the inside of the vehicle where the ground contact pressure increases, especially in vehicles with a negative camber setting, which has recently increased, and as a result, driving and braking on snowy road surfaces. Performance can be increased.

  In FIG. 1, the flow of the groove from the inside of the vehicle to the outside of the vehicle is divided to lower the negative rate of this portion (or increase the contact area), thereby improving the cornering performance and driving / braking performance on ice. In order to obtain the effect, the case where the rib-like land portion row 20 is disposed between the central block row 18 and the side block row 11 located outside the vehicle has been shown, but the present invention is limited to such a configuration. However, it can be provided as needed.

  Further, in FIG. 1, in order to further improve the on-ice brake performance and to reduce the negative rate inside the vehicle, the tire equator narrows between the central block row 18 and the side block row 10 located inside the vehicle. Although the case where the intermediate transverse groove 21 is provided to form the intermediate block row 23 composed of a plurality of intermediate blocks 22 is shown, the present invention is not limited to such a configuration, and is provided as needed. Can do.

  Further, FIG. 1 shows a case where the circumferential sub-groove 14 is constituted by a thick groove extending linearly and the circumferential sub-groove 15 is constituted by a zigzag groove. However, the present invention is not limited to such a configuration. Can be provided as needed.

  Furthermore, in FIG. 1, since the width dimension of the side block 9 located outside the vehicle is large and the rigidity in the tire width direction is relatively high, the side block 9 is prevented from deteriorating uneven wear resistance. Thus, although the case where the longitudinal sipe 24 extending intermittently is shown at a substantially central position in the tire width direction W of the side block 9 is shown, the present invention is not limited to such a configuration and is necessary. It can be provided accordingly.

  The above description is merely an example of the embodiment of the present invention, and various modifications can be made within the scope of the claims.

Next, a pneumatic tire according to the present invention was prototyped and performance evaluation was performed, which will be described below.
Example 1
The tire of Example 1 has the tread pattern shown in FIG. 1, the tire size is 205 / 65R15, the negative rate of the entire tread is 27%, and the negative rate of the tread half-width region located inside the vehicle is 31.2. %, And the negative rate of the tread half-width region located outside the vehicle was 23.1%. The groove widths of the circumferential main grooves 2 and 3 were 5.5 mm, the groove width of the circumferential subgroove 14 was 10 mm, and the width dimensions of the side blocks 8 and 9 were 34 mm and 40 mm, respectively. The composite transverse grooves including the lateral transverse grooves 6 and the lateral transverse grooves 7 are both continuously curved, and the angle with respect to the tire width direction W is 23 ° on the tread end side and 0 ° on the tire equator side. Gradually changed. The side sipes 12, 13 both have an angle of 18 ° with respect to the tire width direction W, the rib-like land portion row 20 and the intermediate block 21 both have 10 °, and the central block has 0 °. The length when projected on a plane including the tire was 105 mm, and the length when projected onto a plane including the tire width direction of the lateral transverse groove 7 was 63 mm. The tire structure other than the tread pattern was the same as that of a normal pneumatic radial tire for passenger cars.

Comparative Example The comparative example has the tread pattern shown in FIG. 3, the tire size is 205 / 65R15, the negative rate of the entire tread is 27.1%, and the negative rate of the tread half-width region located inside the vehicle is 30. The negative rate of the tread half-width region located outside the vehicle was 23.9%. The groove widths of the circumferential main grooves 202 and 203 were 7 mm and 5 mm, the groove width of the circumferential auxiliary groove 214 was 9 mm, and the width dimensions of the side blocks 208 and 209 were 29.5 mm and 33 mm, respectively. The composite transverse groove including the lateral transverse grooves 206 was gradually changed so that the angle with respect to the tire width direction W was 5 ° at the tread end side and 25 ° at the circumferential sub groove 214. The lateral transverse grooves 207 are formed so that the angle with respect to the tire width direction W is 0 ° on the tread end side and 19 ° on the circumferential sub-groove 203 side. The side sipes 212 and 213 had angles of 7 ° and 0 ° with respect to the tire width direction W, respectively.

(Performance evaluation)
(1) Wet Maneuvering Stability Evaluation Test Wet maneuvering stability was evaluated by measuring the limit speed at which a hydroplaning phenomenon occurred on a wet road surface with a water depth of 5 mm and measuring the limit speed.

(2) Steering stability evaluation test on compressed snow Steering stability on compressed snow is determined by braking performance, acceleration, straightness, and cornering by a test driver when traveling in various driving modes on a test track on a compressed snow road. This was done by comprehensively evaluating the feeling.

(3) Brakeability evaluation test on snow pressure The braking performance on snow pressure was evaluated from the measured braking distance by measuring the braking distance when full braking was performed on the snowy road surface from running at 40 km / h.

(4) Drivability evaluation test on the snow pressure The drive performance on the snow pressure was evaluated from the measured time by fully accelerating the surface of the snow pressure and measuring the time to reach a distance of 50 m.

(5) Steering stability evaluation test on ice plate Steering stability on ice plate is determined by braking performance, acceleration performance, straight running performance by test driver when traveling on various test modes on ice plate road surface. The cornering properties were evaluated by comprehensively evaluating the feeling.

(6) Evaluation test of braking performance on ice plate The braking performance on ice plate was evaluated from the measured braking distance by measuring the braking distance when full braking was performed from the traveling speed of 20 km / h on the ice plate road surface. .

From the evaluation results shown in Table 1, the example is superior in handling stability and driving / braking performance on both wet and icy and snowy road surfaces as compared with the comparative example.

  According to the present invention, in particular, the lateral crossing grooves and the side sipes located in the both-side block rows are optimized in the extending direction, and the edge effect when stepping on and kicking out is effectively obtained in the both-side block rows. As a result, it has become possible to provide a pneumatic tire excellent in driving and braking performance on both wet and icy and snowy road surfaces.

FIG. 3 is a development view of a part of the tread portion of the pneumatic tire according to the present invention. It is a conceptual diagram for demonstrating the effect of the pneumatic tire according to this invention. It is a partial development view of the tread part used for the comparative example. It is a conceptual diagram for demonstrating the problem of the conventional tire.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread part 2, 3 Circumferential main groove 4,5 Tread end 6,7 Lateral transverse groove 8,9 Side block 10,11 Side block row | line | column 12,13 Side sipe 14,15 Circumferential subgroove 16 Center Transverse groove 17 Central block 18 Central block row 19 Central sipe 20 Rib-like land portion row 21 Intermediate transverse groove 22 Intermediate block 23 Intermediate block row 24 Vertical sipe

Claims (8)

A pair of circumferential main grooves positioned along the tire equator in the tread portion and extending along the tire circumferential direction, and inclined to the tire width direction, open from the tread end to the circumferential main groove closer to the tire tread. A plurality of side transverse grooves extending at least to form a side block row composed of a plurality of side blocks defined by a circumferential main groove, a side transverse groove and a tread end; In the pneumatic tire formed by arranging the side sipes on each side block,
Both lateral transverse grooves located in the both side block rows have the same inclination, and both side sipes located in the both side block rows are inclined opposite to the inclination of the lateral transverse grooves. A pneumatic tire characterized by comprising: The pneumatic tire according to claim 1, wherein the lateral transverse groove has a continuous curved shape. The pneumatic tire according to claim 1 or 2, wherein the lateral transverse groove has an extension angle with respect to a tire width direction that is large at a tread end position and small at the circumferential main groove position. 4. The pneumatic tire according to claim 1, wherein the side sipe has an extended angle with respect to a tire width direction that is large at a tread end position and small at the circumferential main groove position. Two circumferential sub-grooves extending along the tire circumferential direction and a central transverse groove communicating with both circumferential sub-grooves are disposed between the circumferential main grooves. Forming a central block row composed of a plurality of central blocks partitioned by a central sipe, each central block having a central sipe, wherein both the central transverse groove and the central sipe are substantially parallel to the tire width direction. The pneumatic tire of any one of 1-4. The pneumatic tire according to claim 5, wherein the one side transverse groove communicates with the central transverse groove to form a composite transverse groove. The pneumatic tire according to any one of claims 1 to 6, wherein each of the lateral transverse grooves and the side sipes has an extension angle with respect to the tire width direction of 50 ° or less. The pneumatic tire according to claim 6 or 7, wherein the compound transverse groove located inside the vehicle is longer than the other lateral transverse groove located outside the vehicle when the tire is mounted on the vehicle.

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